BOSTON – Chael Sonnen has long been known for his ground game, but it wasn’t until his victory over Mauricio Rua on Saturday night that he proved how quickly he can finish fights there.

After a back-and-forth first round, Sonnen locked up a guillotine choke late in the opening frame, forcing the former UFC light heavyweight champion to tap out at the 4:47 mark of Round 1.

The light heavyweight bout headlined Saturday’s UFC Fight Night 26 event at Boston’s TD Garden. It aired on FOX Sports 1 as part of the new cable channel’s first day on air.

Sonnen’s trademark style was on display early as he wasted no time diving for the takedown and planting “Shogun” on the mat in the opening seconds of the bout. Rua wasn’t content to stay there long, however, and he quickly scrambled to his feet and got a takedown of his own to even things up.

To Sonnen’s credit, he stayed calm and collected early on, and it wasn’t long before he had reversed the position and resumed the grinding, ground-and-pound style from the top that most people expected from him in this fight. But the real surprise came in the final minute of the round, when Sonnen locked up the guillotine choke and finished it from his back, leaving his Brazilian opponent with no escape route as he squeezed for the submission victory.

After the fight, the always-verbose Sonnen first dedicated his win to his grandmother, who he said has battled cancer, then launched almost immediately into his pro wrestling-style schtick, praising his own performance with an impromptu poem and then calling out longtime Brazilian rival Wanderlei Silva.

“Right here on the UFC’s new home, FOX Sports 1, Wanderlei Silva, 6-feet tall and 205 pounds,” Sonnen said in his post-fight interview with UFC color commentator Joe Rogan. “Boy until I met you, I didn’t know they could stack crap that high.”

After being briefly interrupted by Rogan, Sonnen was soon back on track, offering Silva a fight in three months’ time before storming out of the cage.

With the win, Sonnen (28-13-1 MMA, 7-6 UFC) gets his first victory since January of 2012, snapping a two-fight losing streak that saw him suffer defeats in bouts for both the UFC middleweight and light heavyweight titles. Rua (21-8 MMA, 5-6 UFC) has now lost two in a row in the UFC.

As the UFC 189 tour made its last stop in Dublin, featherweight champ Jose Aldo was met with a torrent of abuse from the Irish fans. It might have been unpleasant, but it might also have been just what he needed.